Delivery mechanism for tissue interfolding apparatus



March 17, 1953 R. N. SABEE 2,631,846

DELIVERY MECHANISM FOR TISSUE INTERFQLDING APPARATUS Original FiledApril 5, 194'? 6 Sheets-Sheet l March 17, 1953 R. N. SABEE 2,631,846

DELIVERY MECHANISM FOR TISSUE INTERFOLDING APPARATUS Original FiledApril 5, 194'? 6 Sheets-Sheet 2 March 17, 1953 R. N. SABEE 2,631,846

DELIVERY MECHANISM FOR TISSUE INTERFOLDING APPARATUS Original FiledApril 5, 1947 6 Sheets-Sheet 4 March 17, 1953 R. N. SABEE 2,631,846

DELIVERY MECHANISM FOR TISSUE INTERFOLDING APPARATUS Original FiledApril 5, 194'? 6 Sheets-Sheet 5 J/r pper a/lgbf/y below lop pas/Wanmawb;dawn. flock new-[y af dawn pas/'flbmmowbg up.

March 17, 1953 R. N. SABEE 2,631,845

DELIVERY MECHANISM FOR TISSUE INTERFOLDING APPARATUS Original FiledApril 5, 1947 6 Sheets-Sheet 6 J'ams ape/7. J'lnkper n) up. Hook (2/ lawpas/Mm.

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fnz/eni 'of fiea'rz/ar'd z jfjal ee Patented Mar. 17, 1953 DELIVERYMECHANISM FOR TISSUE INTERFOLDING APPARATUS Reinhardt N. Sabee,Appleton, Wis., assign'or to International Cell'ucotton ProductsCompany, Chicago, 111., a corporation of Delaware Original applicationApril 5, 1947, Serial No. 739,563. Divided and this application May 13,1949, Serial No. 93,004

4 Claims. (Cl. 270-39) This invention relates to a tissue folding methodand apparatus, and it is particularly (but not exclusively) concernedwith a method and apparatus for interfolding thin, light-weight tissuesof a. soft, flimsy character having but little tensile strength.

In one form of commercial packaging of facial tissues which are typicalof one kind of material which may be folded, two continuous webs oftissue paper (often having two or more plies) are separately fed betweencutting rolls which sever the webs transversely in such a manner as toleave a few very slight bonds connecting the web portions on oppositesides of the line of severance. Such webs are then fed into faceto-facerelation with the lines of severance of one web in staggered relation tothe lines of severance in the other, after which the sheet areas betweensucceeding lines of severance are folded approximatel midway between.the lines of severance. Folding is effected in such a manner that thebonds connecting successive sheet areasof one web are enclosed betweenthe folds of the other web and preferably at the fold line thereof. Theresulting interfolded stack of tissue may be enclosed in a box fromwhich the sheet areas may be successively withdrawn and the leading endof each sheet area automatically pulled out of the boxv upon withdrawalof the preceding sheet.

In order that only one sheet at a time be withdrawn, it is importantthat the bonds be quite weak so as to be easily broken upon theapplication of a small increment of resistance to withdrawal of the nextsection of the same web, while at the same time being strong enough toavoid breakage merely by reason of the slight resistance createdincident to the pulling of the leading end portion. of the other web outof the box. such that. in most known interfolding machinery (much ofwhich is used for interfolding relatively strong paper webs such aspaper towels) is not operative to interfold weakly bonded tissuematerial without breaking the bonds.

The preservation of these bonds is especially important when interfoldedtissue is to be packedv in. boxes of considerable depth (such. asvtypified by facial tissue boxes containing four or five hundred sheets)in which it is especially desirable that the withdrawal of one sheetshould automatically bring to an accessible position, through a narrowdispensing slot, the leading end of the next sheet. Breakage of thebonds would, of course, prevent such automatic feeding of the sheets.This preservation of bond is also highly desirable in connection withthe packaging of continuous: Z.-folded material. which may be alsoproduced by the method and apparatus to be described.

The frailness of the bonds required is so" The specific means formounting these rolls The main objects of the present invention are toprovide a method and apparatus for folding and/or interfolding tissuematerials of the character indicated, and to provide a method and apparatus which will be operative at a very high rate of speed.

Other objects and advantages of the invention will be understood byreference to the fol"- lowing specification and accompanying drawings (5sheets) wherein there is illustrated a folding method and machineembodying a selected. form of the invention.

In the drawings:

Fig. 1 is a vertical section through the work-' ing parts of themachine;

Fig. 2 is a plan section on the line 2-2 of Fig. 1;

Fig. 3 is a vertical section corresponding in part to Fig. 1 but takenin a different plane, certain parts being broken away to betterillustrate certain operating details;

Fig. 4 is a more or less diagrammatic view illustrating an arrangementfor driving the various operating parts of the mechanism;

Fig. 5 is a detail view of an element appearing also in Fig. 1, showingmeans for operating one of the shafts of the machine;

Fig. 6 is a section on the line 6-4; of Fig. 1- on an enlarged scale;

Fig. 7 is a section on the line 1-1 of Fig. 6,.

Figs. 8 to 13, inclusive, are more or less diagrammatic viewsillustrating successive positions of the principal operating elements ofthe mechanism.

This application is a division of my copending application, Serial No.739,563, filed April 5, 1947.

As shown in Fig. 1, the machine embodies a unit of mechanism. designatedin its entirety by the reference numeral I, said unit embodyingcooperating cutter roll pairs 2 and 3, the roll pair 2 embodying a kniferoll 4 and an anvil roll 5 and the roll pair 3 embodying similar knifeand anvil rolls 6- and 1, respectively. Paper webs 8 and 9 are fed oversuitable guide rolls in and H for the web- 8 and a roll ['2 for the web9 to feed roll pairs I3 and I4, respectively. The feed roll pair I3embodies cooperating rollsl5 and 16, at least one of which is positivelydriven at a predetermined rate of speed to effect travel of the web 8 atthe desired rateof travel. Similarly, the roll pair l4 comprises rollsl1 and I8, at least one of which is positively driven at" apredetermined rate of speed to propel the web- 9 at the required speedwhich is the same as the speed of travel of the" Web 8. The rolls ofthe. feedv roll pairs [3 and M are preferably ad justably' mounted so asto facilitate control of the pressure with which the webs fed between:

them are gripped by the respective roll pairs.

forms no part of the present invention, and is, therefore, not describedin detail.

In the arrangement illustrated, the knife andseverance formed in the web8 will be located substantially midway between successive lines ofseverance formed in the web 9 when the webs 8 and 9 are delivered inface-to-face relation from between the anvil rolls and l as shown inFig. 1.

Commercial forms of facial tissue are usually in the neighborhood of teninches in width. It is convenient to interfold a double width of tissueand to subsequently break the double width into separate sections of therequired width. Accordingly, the apparatus is provided with slitters i9and 20 carried on the free ends of the arms 21 and 22, respectively,which are suitably pivotally mounted through the agency of supportingshafts'carried by the frames of the upper unit of mechanism.

The slitters i9 and 2?! are preferably enclosed by suitable guards 23and 24 which are carried by the arms 2| and 22, and weighted arms 25 and26 associated with the respective slitter arms 2| and 22 serve to urgetheslitters I5 and it toward the respective guide rolls H and 12 withsufiicient force to slit webs 8 and 8 longitudinally intermediate theirwidths. The slitting is not quite complete and does not actuallyseparate the webs into two strips, sufficient but easily breakablebonding remaining to preserve continuity of the divided webs.

The mechanism for Z-folding and for interfolding the paper, is supportedby side frames immediately below the above-described web feecling,slitting and severing mechanism. The webs 8 and 9 in face-to-facerelation travel downward- 1y between a pair of folding rolls 2! and 28which are carried respectively by shafts 29 and 3B which are suitablyjournalled in. the side frames 3| and 32, respectively, of the mechanism(see Fig. 2). The rolls 2? and 28 are so mounted relative to each otherthat their surfaces are spaced apart a distance which will cause therolls to guide the webs 8 and 9 downwardly between them without grippingor exerting any positive feeding effect. The rolls are continuouslyrotated in opposite directions, the roll 2'! being rotated clockwise andthe roll 28 counterclockwise as viewed in Fig. 1. 7

Each of the rolls 27 and 28 carries three sets of jaws and threetuckers, the tuckers being located intermediate the pairs of jaws. Inthe present embodiment of the invention, three pairs of tucker-s andthree jaws are employed, but it is apparent that by using smaller orlarger earrying rolls, or to adapt the apparatus to the interfolding oftissue sheets of shorter or longer length than those for which thepresent machine is designed, or for other reasons, the number of jawsand tuckers may be varied.

7 The roll 21 is provided with jaw pairs each embodying a fixed jawelement 33 and a movable jaw element 34. The tuckers provided in theroll 21 are indicated by the reference numeral 35, these tuckers beingfixedly mounted in the roll. Similarly, the roll 28 has tucker jawscomprising a fixed jaw 36. a movable jaw 37 and fixed tuckers 38. Thejaws and tuckers extend for the entire length of the respective rolls,but they are grooved transversely in conformity with the groovesprovided in the rolls 2? and 28 for the reception of certain elementswhich wi11pres ently be described. Certain of such grooves are indicatedat 39 and in the rolls 2'! and 28 respectively, in Fig. l. The movablejaws 34 are formed with short shaft sections 4i intermediate the lengthsof the jaws and at their ends. The jaws are rockably positioned ingrooves 62 in the body of the roll 27. Similarly, the movable jaws 31 ofthe roll 28 are provided with intermediate and end shaft sections 43,and grooves 44 in the roll receive the jaws. The intermediate shaftsections 4! and 43 are located in alignment with the grooves 39 and 40and in the respective rolls and are seated in bearing surfaces preparedfor that purpose. Bearing caps 45 and 36 bolted to the rolls 2'! and 28over the jaw shaft sections hold the jaws in place.

The end shaft sections 42 and 43 which project beyond the ends of therolls are provided with arms which carry rolls at their free ends forengagement with cams whereby the jaws may be rocked in predeterminedsynchronism with cooperating elements of the mechanism. One of thecam-operating mechanisms is shown in Fig. 2 wherein the projecting endshaft H of the roll 2? is shown as being provided with an arm 451. Thearm 41 is provided at its free end with a roller 8 for engaging theinternal cam surface 49 carried by a cam body 50 which is rotatablyadjustably mounted as indicated at El in the frame 3! in co-axialrelationship to the shaft 29 of the roll 2?. The roller 48 is urged intoengagement with the cam surface 49 by means of a spring 52 (see Fig. 3)compressed between spring seats 53 and 54, the spring seat 53 beingfixedly mounted on the member 56 which is fastened on the end of theroll, and the spring seat 54 being carried by the free end of the armd8. To prevent the accumulation of lint and other foreign material onthe surface of the cam 49, the space between the end of each roll andits'associated cam, is closed by means such as circular housing elements55 which are bolted or otherwise secured to the adjacent ends of the cambodies 5|, and said roll end members 56 which have flanges 51 spacedinwardly from the housings 55. The space between the housings 55 andflanges 57 is sealed by suitable packing rings such as represented at58.

As shown in Fig. 1, the rolls 2! and 28 with their alternate jaw pairsand tuckers are so related to each other that each tucker and one rollcooperates with a pair of jaws of the other roll. The arrangement issuch that each tucker tucks the webs 8 and 9 of tissue into theopposite.

or cooperating jaw pair while the jaws are open, the tucker being alsofully withdrawn from between the jaws before they close and before thejaws actually grip the tucked in webs. This method of operation isclearly illustrated in Figs. 8 to 13, inclusive, in which Fig. 8illustrates the position of a tucker and its cooperating jaw pair atabout the time of first contact thereof with the web to be folded (orthe webs to be interfolded). In the present embodiment, this positionoccurs when the point of the tucker 38 is located in registry with aradius extending upwardly at an angle of about 12 from a horizontalradius of the roll.

Figs. 9 and 10 show succeeding positions and corresponding webpositions, Fig. 9 representing a position in which the point of thetucker is in registry with a radius extending upwardly at an angle of 6from a horizontal radius of the roll 28, and Fig. 10 representing thecondition in which the tucker point is in registry with the horizontalradius of the roll 28.

It may be ob-- provision (a), and by pulling up on the web to take upsome of the slack resulting from the aforesaid provision (b). By takingup the incoming slack, accumulation of web material immediately ahead ofthe folding rolls is prevented and tensioning of the incoming materialis avoided because of the freely available slack S from which is drawnthat portion of the material required to form the tucked-in-loop whichis in excess of the slack freely available from the incoming webportion. Possibly, most of the tuck material is drawn from the slackbelow the folding rolls, but in any event the tuck is formed by takingup slack material, thereby avoiding tensioning of any portion of thematerial. It should be observed that the slippage of the web between thefolding rolls is slightly resisted by the rollsurfaces sothat the webdoes not drop down between the rolls as fast as it is delivered by thefeed rolls; therefore, slack is produced both above and below thefolding rolls.

The interfolded webs are delivered to a stack located immediately belowthe rolls 2? and 28, such stack being formed between guide posts orfingers 59 and '68 which are supported at their lower ends on transverserods El and 92. The rods 5| and 52 are carried by bracket members suchas 83 and 64 which are fastened to the side frames of the machine. Thestack guide members 59 and 69 respectively, extend upwardly intosuitable grooves 61 and 68 in the rolls 2! and 28, there being asufficient number of these guide members 59 and 60 spaced across thelengths of the rolls to adequately support the tissue stack as shown inFig. 1 (see also Fig. 2). The guides 58 and 60 are, in effect, extendeddownwardly by tissue channel-forming plates 69 and I0, which are alsosupported by attachment to the said brackets 53 and 64. The plate H1 isextended forwardly at an angle as indicated at II to form the top wallof a horizontally and downwardly extending chute or channel, the bottomwall of which is formed by the upper reach of a conveyor belt 12. Theguide plate 69 terminates a short distance above the conveyor belt 72 asshown. The belt i2 is normally driven at a very slow rate of speedapproximately corresponding to the rate of travel of the stack oftissues resulting from the addition of folded sheet after sheet to thetop of the stack and downward feeding of the stack top by stripping andhold-down devices presently to be described.

' The belt 12 is driven from a pulley 13 (Fig. 1) carried by a shaft 14which is suitably journalled in the frame structure of the machine. At asuitable point in the length of the shaft 74 it has secured to it aclutch disc 75 (see Fig. 5) which'is surrounded by a clutch ring 16. Theclutch ring 16. is rocked and has an operative connection to the clutchdisc E5 of such character that when the ring 16 moves in one direction,the disc 15 and shaft M will be advanced while movement of'the ring 15in the opposite direction will be independent of any movement of thedisc I5 and shaft 14. Any suitable one-way clutch may be employed, andin this instance, it is represented as constituting a ball type ofclutch embodying one or more balls or rollers Tl housed in recesses suchas 18 in the disc 15 and grooves such as 19 in the ring 16. The bottomsof the recesses it are so related to the circumference of the disc thatwhen the ring 16 turns in one direction, the balls will become wedgedbetween the bottoms of the grooves 19 and the bottoms of the recesses 18so as to effect unitary movement of the ring 76, the clutch disc 15 andshaft 14. Movement of the ring in the other direction serves, of course,to release the clutch balls or rollers so that reverse movement of thering 76 is not imparted to the disc and shaft".

The ring 16 is provided with an arm 80 (see Fi 1) which is slotted toadjustably receive a pivot block 8|. The position of the pivot block 8|in the slotted arm may be adjusted and fixed by any suitable means suchas an adjusting screw 82 and a lock nut 83 to thereby facilitateadjustment of the amount of travel imparted to the belt by eachoperative movement of the clutch ring. Rocking motion is imparted to thearm 8| by means of an eccentric 84 carried by a shaft 85 suitablyjournalled in the machine frame. An eccentric ring 86 surrounds theeccentric 84 and is connected to the clutch arm 89 by means of an arm 81formed integrally with the ring and piv oted to the block 8|. 7

The shaft 85 is continuously rotated by a suitable driving connection,one of which will here.- inafter be explained.

The jaws 33 and 34 of the roll 21 and the jaws 3B and 31 of the roll 28serve to alternately deposit web folds at the opposite sides of thestack. To insure stripping of the folds from the jaws which areautomatically opened as they approach the vertical planes of the frontand rear sides of the stack, there are provided a plurality of stripperarms 88 and 89 respectively associated with the rolls 21 and 28, thegrooves 39 and 40 previously referred to, serve to receive suchstrippers in their elevated positions. The strippers 88 and 89 arecarried respectively by shafts 9|] and 9| which are suitably journalledin the side frames of the machine and these shafts together with theirstrippers are rocked in properly timed relation to the travel of thejaws of the respective rolls so that the end or finger portions 88a and89a of the respective strippers will be operative to strip the foldedwebs from the jaws of the respective rolls and pack the folded web downon top of the stack of folded tissues.

The shaft 90 is rocked by means of an arm 92 which is carried by theshaft 90 and connected by means of a pin and slot connection to an arm93 which has an eccentric ring 94 surrounding an eccentric disc 95carried by a driven shaft 96. The shaft 9| is rocked by similaroperating connections to an eccentric 91 carried by a driven shaft 98.The pin and slot connections in the arms serve to permit adjustment ofthe throw of the stripper fingers 88a and 89a and their timing may beadjusted by adjustment of the eccentric discs 95 and 9'! about theshafts 96 and 98. In addition, the arm 92 on the shaft 90 and itscounterpart on the shaft 9| may be adjustably connected to the shaft topermit adjustment of the position of the respective stripper fingers.

When one of the stripper fingers 88a or 89a is in a down position (inwhich the stripper 88a is illustrated in Fig. 1) the other stripper isin an elevated position. Also, the stripper fingers have an intermediateposition in which they are both located about midway between their upperand lower positions. In orderto hold the top of the stack against upwarddisplacement when the stripper fingers 88a and 8911. are in elevatedrelation to the normal top level of the stack, there are providedholding arms or hooks 99 and 100 respectively carried by shafts IN and I02 which are rockably mounted in the frame sides of the machine. Thearms 99 and I00 are provided at their upper ends with heads I03 and I 04respectively which move from .a position overlying the respectivemargins of the stack to retracted positions clear of the top area of thestack. In their retracted positions the heads of the holddown arms arereceived in the aforementioned grooves 39 and 40 at the sides of therespective stripper fingers 88a and 89a as indicated in Fig. 2. Thehold-down arms 99 and E are secured to the shafts IllI and I02 which arerocked in suc synchronism with the movement of the stripper fingers thatthe hold-down members are brought into operative engagement with the topof the stack before the associated stripper finger leaves the top of thestack. Therefore the top of the stack is at all times restrained againstupward movement beyond a desired level.

The shafts IUI and IE2 may be rocked in the required timed relation tothe operation of the strippers by any suitable means. such as typifiedby cams I and I9 3 carried by a frame carried stub shaft represented atIN. The cams are rotated by a suitable connection to one of the otherrotating parts of the machine whereby the proper timed relationship willbe maintained. The cams I05 and I96 respectively act against rollerscarried at the free ends of arms H38 and IiiEI which are respectivelysecured to the rock shafts IilI and I02. 7

The arrangement is such that the top of the stack of interfolded sheetsis located very close to the surface of the folding rolls whereby thefolded web can be deposited on the top of the stack with a minimum oftravel time. By maintaining the top of the stack ver close to the surfacof the interfolding rolls, the extent of movement required to beimparted to the stripping fingers and to the hold-down members is keptat a minimum whereby high speed operation of the machin is greatlyfacilitated. The top of the stack i so close to the surfaces of thefolding rolls that light contact may occur where the stack bulgesupwardly between adjacent strippers and holddown hooks. The angularpositions of th tuckers and the leadingjaws are such that these partsmore or less cam the stack top dOWnWardly inCldent to their passage overthe stack without an plying an adverse sidewise force to the stack.Apparently, because of the high speed at which the rolls rotate, thestack does not have time to expand upwardly into' the path of thetrailing Crepe tissue wadding and other material of the character whichmay be folded or in'terfoldedby thede'scr'ibed apparatus is apt to varyconsider ably in bulk incident to changes" in atmospheric conditions.Under some conditions the tissue webs will have considerably greaterbulk than under other conditions. Manufacturing processes may also havea bearing on the variation inthe bulk of the crepe tissu which isdelivered to the folding machine and this variation in bulk may occurwithin each separate run or roll of tissue delivered to the interfoldingmachine. These variations in bulk, especially an increase in bulk, willtend to alter the level of th top of the stack. While the level cannotactually be altered due to the positive action of the strippers andhold-down members, the variation does tend to create such expansive backpressure in the stack of folded tissues that'normal operation of thestrippers and hold-down fingers at high speeds is hampered.

Thenormal feed of the stack of interfolded tissuesby the conveyor belt12 can easily be dc- 10 signed to handle the tissues when deliveredconstantly under their minimumbulk conditions. However, when the bulkisincreased the normal stack feed produced by the belt 12 will be slowwith the result that the stack tends to expand at its top or receivingend. To prevent establishment of the indicated back pressure and therebyto maintain normal working conditions for the strippers, means have beenprovided for accelerat ing the speed of travel of the conveyor belt 1when back pressure of the top of the stack requires it. This means iscompletely automatic. 7,

The control means for accelerating the rate of travel of the stackfeeding belt I2 consists in the provision of pressure sensitive stripperarms 31d:- jacent the ends of the roll 28 inplace of normal stripperarms, such as represented by the arms 89. The pressure sensitivestripper arm arrangement (shown in Fig; 3) consists of a main armportion I I0 mounted on the shaft 9| so as to rock as a unit with thenormal stripper arms 89. The arm IIIl has a supplemental arm III pivotedon it as indicated at H2, the supplemental arm extending in oppositedirections beyond the pivot II 2. The inner end of the arm III isprovided with a stripping finger IIIa which corresponds to the strippingfingers 89a and the opposite end of the arm III is provided with anadjustable screw I 53 which is adapted to actuate the control pin I Idof a suitable electric switch II5 which is mounted on a downwardextension of the main arm I It. The screw I I3 actuates the control pinvof the switch through the agency of a flat leaf spring I It so thatgreat accuracy is not required in the matter of aligning the screw ,I I3and con trol pin IM of the switch. 7 A suitable tension spring II1 isanchored at its upper end to the top of the arm III, extends downwardlythrough a hole in the arm and is connected to an adjusting screw IIBwhich is threaded through a lug II9 on the arm H0. The spring III servest'o normally hold the supplemental arm III seated on the lug or seat 523of the main arm III]. The tension of the spring II'I may be adjusted byap propriately adjusting the screw II8.

In the event that the stack of tissue begins to offer excessiveresistance to the normal down= ward movement of the stripper fingers tothe plane of the top of the stack, the arm III will be caused to rock onits. pivot II2 against the tension of the spring II'I. Such rockingmovement will close the switch I I5 and thereby establish an electriccircuit which controls an electric motor I2I (Fig. l) which is employedvfor driving the conveyor belt 72 independently of, and in addition tothe normal drive of the belt as already explained. The electric circuitclosed by. the switch H5 is suitably connected to a time delay relay I22which may be any one of many suitable constructions, many of which arecommerciallyv available. The time delay relay I22 serves, each time itis actuated, to close fora definite time; period, an electric circuit toa motor starter I23 which is suitably electrically connected to themotor I2 I. Hence, each timethat the switch I I5 is closed, the motorI2I will be actuated for a predetermined time period during which;through connections about to be described, the tissue stack feed belt I2will be advanced. This time interval during which the motor I2I is operated may be any time interval which eXperi-, ence indicates to bedesirable, for example, two or three seconds. A stop screw IIIla carriedby a portion of the arm I I0 serves to limit the rock: ing movement ofthe arm III relative to the main 11 arm H and thereby protects theswitch II from excessive pressure from the arm III and also insuresproper stripping action and stack top holding or depressing performanceof said arm as shown in Figure 8.

The motor I2I operates through a suitable speed reduction meansindicated generally at I24 todrive a sprocket I25. A chain driverepresented at I26 from the sprocket I25 to a shaft I2'Iserves to efiectrotation of a worm gear I28 on the shaft I27. Said shaft I2! is suitablyjournaled in a bracket member I29 provided for that purpose and the wormgear I28 meshes with a worm wheel I30 which is rotatably mounted on theshaft 74. Rotation of the worm wheel I30 when driven by the motor I2 I,is imparted to the conveyor drive shaft 14 through the agency of a pawlI3I carried by the worm wheel and a ratchet I32 which is pinned orkeyed'to the shaft I4. The pawl I3I is spring pressed into engagementwith the ratchet I32 and it is faced in such a direction that when theworm wheel I30 is driven by the motor I2I rotation will be imparted tothe shaft I4 while rotation of the shaft 14 may be imparted from thenormal driving shafts already explained without tending to drive theworm wheel reversely.

Each time that excessive. back pressure develops in the receiving end ofthe tissue stack, one or both of the pressure sensitive stripper fingers(there being one at each end of the folder roll 28), will be actuated toproduce the described accelerated feed of the stack to thereby relievesuch pressure. Hence, the development of sufficient back pressure tointerfere with normal operation of the strippers and hold-down fingersis not permitted to develop.

a As shown in Fig. 2, there is a groove or recess in the middle portionof each of the rolls 2'! and 28 which is approximately twice the widthof the grooves 40 for receiving the normal stripper fingers 89 and thepressure sensitive stripper fingers IlIa. These enlarged grooves receivestripper fingers 88b and 8% which are widened as compared with thenormal strippers 88a and 89a so as to extend well beyond both sides ofthe longitudinal slit in the interfolded webs. This pro-' vision ofwidened fingers avoids the localization of pressure near thelongitudinal slit; distortion of the webs at the slits which would tendto break the remaining bond is thereby avoided.

One arrangement of driving connections for the various parts of themachine is illustrated in Fig, 4. For driving purposes one of the shafts29 or 30 may be driven by a suitable chain drive connection to anelectric motor, this primary drive being not shown. The shafts 29 and 30are geared together by gears represented at I33 and I34 secured to therespective shafts 29 and 30. The shafts 96 and 98 may be driven inproperly timed relation to the drive of the interfolding rolls by meansof gears represented at I35 and I36 carried by the respective shafts 96and 98 and meshing with the gears I33 and I34 respectively. For drivingthe shaft 85 from which the normal feed of the tissue stack is obtained,there may be provided a chain drive represented at I31 from a suitablesprocket mounted on the roll shaft 29 to engage a suitable sprocketmounted on the eccentric shaft 85. The hold-down actuating cams wmcn arecarried by the shaft I01 may also be driven by a chain I38 which engagessuitable sprockets carried by the respective shafts 30 and I01.

The shafts I39 and I40 of the cutter roll pair 3 and the shafts I 4| andI42 of the cutterroll pair 2 may be driven by means of an idler gear I43which meshes with a gear I44 on the interfolder roll shaft 29 and a gearI45 on the cutter roll shaft I40. The gear I45 meshes with another gearI46 on the knife roll shaft I39 and with a gear I41 on the cutter rollshaft I42, said gear I41 also meshing with a gear I48 on the cutter rollshaft MI. The innermost rolls of the web feed roll pairs I3 and I4 maybe driven from the respectively adjacent gears I45 and I4! of the anvilrolls through the agency of gears I49 and I50 secured to the respectivefeed roll shafts and meshing with the respectively adjacent anvil rollgears I 45 and I41. The outer rolls I5 and I8 of the tissue feed rollpairs may be fractionally driven from the inner rolls, said outer rollsbeing arranged to gravitate toward the driven inner rolls or providedwith spring means urging them toward said inner rolls. The gears andsprockets for the chain drives are, of course, properly-selected as totheir pitch diameters and number of teeth to produce the requiredrotation of the various driven parts. r

The described machine is operable at much higher speeds than haveheretofore been attained in folding machines of the general characterdescribed. Operation at a speed to produce 800 folds per minute (400folds at each side of the stack) is entirely feasible and practical, andit appears that some increase may be anticipated.

Some of the main factors which make possible this high speed operationcomprise the simplification of the folding rolls to employ fixedtuckers, and gripping jaw pairs embodying only one movable jaw withattendant simplification of operat-- ing mechanism; the avoidance orelimination of snap action mechanisms facilitates, said high speedoperation with a minimum of shock and strain on the machine and the Web,thereby attaining durability of the machine, freedom from breakdowns ofthe machine and the web and quietness of operation; the free anduntensioned web arrangement which permits the tucks to be made in thedescribed manner without pulling the web taut at any point whereby bondbreakage is avoided; the use of rubber friction tips to control thetucked-in web, i. e. to preventwithdrawal of the web by the tuckerincident to .retraction of the latter from between a pair of jaws; theuse of said friction jaw tips to aid in retaining the folds in the jawsagainst premature discharge therefrom upon being opened, even thoughopening of the jaws is started in advance of the desired point of folddischargethe nearly radial or sharply inwardly folded position ofthefolds between the jaws probably also helpsoto insure web fold retentionin the jaws sufiiciently to draw the deposited web smoothly across thestack without also pulling the web from under the strippers or hold-downfingers at the opposite side of the stack; the resilient character ofthe jaw tips which permits the jaws to come tightly together to grip thewebs without requiring extreme, if not practically unobtainable,accuracy in respect to the size and extent of movement of the movablejaws in apparatus designed to operate at the indicated high speed;positioning of the top of the stack of folded material close to thefolding roll surfaces so as to reduce the extent of travel required ofthe strippers and of the folded web upon its release from the foldingjaws; and maintenance of a substantially con-:

stant pressure reaction of the folded stack on the stripper fingers.There are perhaps other fac tors, but those mentioned are probably themost important.

In the arrangement described, the tuckers and jaws are so related thatthey do not pinch the web between them; in some instances, it may bedesirable that one or the other of the jaws be so related to the tuckeras to more or less brush or wipe the web from the tucker incident torecession of the tucker from between the jaws. Material which may behandled by the described apparatus (subject to suitable adjustment ofthe spacing of the folding rolls to preserve the required paper slipbetween the rolls) may be typified by: (a) tissue paper having a dryerbasis weight of about 7.64 pounds per ream (480 sheets) 24" x 36"; (b)said tissue paper (a) after creping so as to have a basis weight ofabout 10.5 pounds per ream of sheets 24" x 36"; and double ply crepedtissue paper such as used for making commercially available facialtissues, the basis weight for such double ply material being about 19.1pounds per ream of 480 double ply sheets 24" x 36". These basis weightsare set forth merely as typical of the kind of light-weight and flimsymaterial which can be successfully folded and interfolded; limitation ofoperativeness to these weights is not to be implied from thisrecitation.

Various changes in the described apparatus may be made, and theapparatus may be employed for either Z-folding or interfolding purposes(this depending on the number and arrangement of webs fed to the foldingrolls), while retaining the principles of the invention. In thefollowing claims, reference to Z-folding will, of course, includeinterfolded sheets as produced by the described apparatus since theinterfolded sheets include, in effect, two Z-folded webs.

I claim:

1. Sheet material folding apparatus of the class described comprising areceiver for the folded material, means associated with said receiverfor propelling the stack of material in said receiver from the intakeend thereof at a predetermined rate, an arm movable toward and from thereceiving end of said stack, pressure sensitive means carried by saidarm, engageable with the receiving end of said stack and adapted to beactuated upon encountering excessive resistance to normal movement ofsaid pressure sensitive means with said arm incident to inadequatemovement of stack from the intake end of said receiver, and auxiliarymeans, activated by said pressure sensitive means when actuated asaforesaid, for effecting accelerated movement of the material in saidreceiver to relieve said resistance.

2. In combination, mechanism of the class described having means whichfolds and delivers a succession of paper sheets into a stack,oscillating pressure means repeatedly engaging and pressing the top ofsaid stack away from said delivering means, a conveyor for receiving andcarrying said stack away from said delivering means, means normallydriving said conveyor at a predetermined rate of travel adapted tomaintain the top of said stack in predetermined relation to saiddelivering means, said pressure means embodying a member which isnormally movable in unison with said pressure means into engagement withthe top of said stack, said member being also movable relative to saidpressure means as an incident to excessive resistance of the top of saidstack to movement away from said delivering means, and means actuated asan incident to such movement of said member to effect, for a limitedtime period, stack movement which is accelerated relative to theaforesaid normal movement thereof, thereby to reduce said excessiveresistance.

3. In combination, mechanism of the class described having means whichfolds and delivers a succession of paper sheets into a stack,oscillating pressure means repeatedly engaging and pressing the top ofsaid stack away from said delivering means, a conveyor for receiving andcarrying said stack away from said delivering means, means normallydriving said conveyor at a predetermined rate of trave1 adapted tomaintain the top of said stack in predetermined relation to saiddelivering means, said pressure means embodying a member which isnormally movable in unison with said pressure means into engagement withthe top of said stack, said member being also movable relative to saidpressure means as an incident to excessive resistance of the top of saidstack to movement away from said delivering means, an electric switcharranged to be closed by said member when moved relative to saidpressure means as aforesaid, and electrical means controlled by saidswitch for initiating movement of said conveyor at a higher-thannormalrate of travel to thereby relieve said excessive resistance.

4. In combination, mechanism of the class described having means whichfolds and delivers a succession of paper sheets into a stack,oscillating pressure means repeatedly engaging and pressing the top ofsaid stack away from said delivering means, a conveyor for receiving andcarrying said stack away from said delivering means, means normallydriving said conveyor at a predetermined rate of travel adapted tomaintain the top of said stack in predetermined relation to saiddelivering means, said pressure means embodying a member which isnormally movable in unison with said pressure means into engagement withthe top of said stack, said member being also movable relative to saidpressure means as an incident to excessive resistance of the top of saidstack to movement away from said delivering means, a normally idleelectric motor connected to said conveyor for driving the same at a rateof travel thereof which is greater than said predetermined rate and soas to permit normal travel of said conveyor while said motor remainsidle, an electric switch arranged to be closed by said member when movedrelative to said pressure means as aforesaid, and electrical meanscontrolled by said switch for energizing said motor for a predeterminedtime period to thereby effect accelerated travel of said conveyor forsaid predetermined time period, thereby to relieve said excess pressure.

REINHARDT N. SABEE.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,003,446 Gauch Sept, 19, 19112,017,044 Graf et al. Oct. 15, 1935 2,094,938 Blatzheim Oct. 5, 19372,116,782 Deloye May 10, 1938 2,449,663 Marcalus Sept. 21, 1948 FOREIGNPATENTS Number Country Date 607,496 Great Britain Sept. 1, 1948

